android很實用的工具類

 
public class CommonUtil {


public static boolean hasSDCard() {

    String status = Environment.getExternalStorageState();
    return status.equals(Environment.MEDIA_MOUNTED);
}

/**
 * 獲取最大內存
 * 
 * @return
 */
public static long getMaxMemory() {

    return Runtime.getRuntime().maxMemory() / 1024;
}

/**
 * 檢查網絡
 * 
 * @param context
 * @return
 */
public static boolean checkNetState(Context context) {

    boolean netstate = false;
    ConnectivityManager connectivity = (ConnectivityManager) context
            .getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivity != null) {

        NetworkInfo[] info = connectivity.getAllNetworkInfo();
        if (info != null) {
            for (int i = 0; i < info.length; i++) {

                if (info[i].getState() == NetworkInfo.State.CONNECTED) {

                    netstate = true;
                    break;
                }
            }
        }
    }
    return netstate;
}

public static void showToast(Context context, String tip) {

    Toast.makeText(context, tip, Toast.LENGTH_SHORT).show();
}

public static DisplayMetrics metric = new DisplayMetrics();

/**
 * 得到屏幕高度
 * 
 * @param context
 * @return
 */
public static int getScreenHeight(Activity context) {

    context.getWindowManager().getDefaultDisplay().getMetrics(metric);
    return metric.heightPixels;
}

/**
 * 得到屏幕寬度
 * 
 * @param context
 * @return
 */
public static int getScreenWidth(Activity context) {

    context.getWindowManager().getDefaultDisplay().getMetrics(metric);
    return metric.widthPixels;
}

/**
 * 根據手機的分辨率從 dp 的單位 轉成為 px(像素)
 */

public static int dip2px(Context context, float dpValue) {
    final float scale = context.getResources().getDisplayMetrics().density;
    return (int) (dpValue * scale + 0.5f);
}

/**
 * 根據手機的分辨率從 px(像素) 的單位 轉成為 dp
 */
public static int px2dip(Context context, float pxValue) {

    final float scale = context.getResources().getDisplayMetrics().density;
    return (int) (pxValue / scale + 0.5f);
}

/**
 * 查詢手機內非系統應用
 * 
 * @param context
 * @return
 */
public static List<PackageInfo> getAllApps(Context context) {

    List<PackageInfo> apps = new ArrayList<PackageInfo>();
    PackageManager pManager = context.getPackageManager();
    // 獲取手機內所有應用
    List<PackageInfo> paklist = pManager.getInstalledPackages(0);
    for (int i = 0; i < paklist.size(); i++) {
        PackageInfo pak = (PackageInfo) paklist.get(i);
        // 判斷是否為非系統預裝的應用程序
        if ((pak.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) <= 0) {
            // customs applications
            apps.add(pak);
        }
    }
    return apps;
}

public static Bitmap zoomBitmap(Bitmap bitmap, int width, int height) {
    int w = bitmap.getWidth();
    int h = bitmap.getHeight();
    Matrix matrix = new Matrix();
    float scaleWidth = ((float) width / w);
    float scaleHeight = ((float) height / h);
    matrix.postScale(scaleWidth, scaleHeight);
    Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
    return newbmp;
}

/**
 * 獲取版本號和版本次數
 * 
 * @param context
 * @return
 */
public static String getVersionCode(Context context, int type) {

    try {

        PackageInfo pi = context.getPackageManager().getPackageInfo(
                context.getPackageName(), 0);
        if (type == 1) {

            return String.valueOf(pi.versionCode);
        } else {

            return pi.versionName;
        }
    } catch (NameNotFoundException e) {

        e.printStackTrace();
        return null;
    }
}

// 通過Service的類名來判斷是否啟動某個服務
public static boolean messageServiceIsStart(
        List<ActivityManager.RunningServiceInfo> mServiceList,
        String className) {

    for (int i = 0; i < mServiceList.size(); i++) {
        if (className.equals(mServiceList.get(i).service.getClassName())) {

            return true;
        }
    }
    return false;
}

}
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